Extensions to the PUIST user interface specification tool

PUIST is a specification tool that is being created for software development. It assists user interface designers to specify the static form and dynamic behaviour of graphical user interfaces (GUI) using a Petri net based model. We describe extensions made to increase the modelling power of PUIST and to make it more practical. Hierarchical specifications have been introduced to PUIST which make modular design, specification reuse and top down design possible. Two special types of arc and one special type of transition have also been introduced to PUIST to extend the range of the dynamic behaviours PUIST can specify. In particular the dynamic behaviours of a menu can now be precisely specified